sedimentary

Diatomite

Diatomaceous Earth (mostly SiO2·nH2O)

AI-generated identification · may be incorrect

Hardness: 1-1.5 (Mohs), Color: White, cream, or light grey, Luster: Dull or earthy, Texture: Fine-grained, friable, and porous, Specific Gravity: 1.9-2.35

Hardness: 1-1

Identified June 28, 2026More sedimentary →

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Physical properties

Hardness: 1-1.5 (Mohs), Color: White, cream, or light grey, Luster: Dull or earthy, Texture: Fine-grained, friable, and porous, Specific Gravity: 1.9-2.35

Formation & geological history

Formed by the accumulation of the siliceous remains (frustules) of diatoms, which are microscopic unicellular algae, in marine or lacustrine environments.

Uses & applications

Used as a filtration aid, mild abrasive in toothpastes/metal polishes, absorbent for liquids, insecticide (mechanical action), and thermal insulator.

Geological facts

Diatomite is so light and porous that dry specimens can often float on water briefly. It was used by Alfred Nobel to stabilize nitroglycerin to create dynamite.

Field identification & locations

Identify in the field by its very light weight, ability to easily powder when scratched, and a tendency to stick to the tongue due to extreme porosity. Found in ancient lake beds and seafloors.